Summary
Kubewarden: Cross-namespace data exfiltration via deprecated host callback binding
Workarounds
Kubewarden operators can update the policy-server image used by their PolicyServers to tag :v1.33.0.
Alternatively, Kubewarden operators can temporarily reduce the permissions of users to prevent them from creating or updating existing namespaced AdmissionPolicies or AdmissionPolicyGroups.
Impact
Kubewarden is a policy engine for Kubernetes. Kubewarden cluster operators can grant permissions to users to deploy namespaced AdmissionPolicies and AdmissionPolicyGroups in their Namespaces. One of Kubewarden promises is that configured users can deploy namespaced policies in a safe manner, without privilege escalation.
An attacker with privileged "AdmissionPolicy" create permissions (which isn't the default) could make use of 3 deprecated host-callback APIs: kubernetes/ingresses, kubernetes/namespaces, kubernetes/services.
The attacker can craft a policy that exercises these deprecated API calls and would allow them read access to Ingresses, Namespaces, and Services resources respectively.
This attack is read-only, there is no write capability and no access to Secrets, ConfigMaps, or other resource types beyond these three. The attacker could read for example:
- Namespace names and labels.
- Services across all namespaces with ClusterIPs and ports to reveal cluster internal topology.
- Ingresses across all namespaces with hostnames and routing rules.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-29773 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.33.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
The vulnerable, already deprecated host-capabilities (kubernetes/ingresses, kubernetes/namespaces, kubernetes/services)
have been removed.
The removed calls were not being exercised by any Kubewarden SDK.
These host-callbacks had already been superseded for a long time by kubewarden/kubernetes/list_resources_by_namespace, kubewarden/kubernetes/list_resources, and kubewarden/kubernetes/get_resource. They provide similar capabilities while being more fine-grained, performant, and gated through our context-aware permissions feature. These current host-capabilities are part of the Kubernetes capabilities listed in our docs.
Frequently Asked Questions
- What is CVE-2026-29773? CVE-2026-29773 is a medium-severity incorrect authorization vulnerability in github.com/kubewarden/kubewarden-controller (go), affecting versions < 1.33.0. It is fixed in 1.33.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-29773? CVE-2026-29773 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/kubewarden/kubewarden-controller are affected by CVE-2026-29773? github.com/kubewarden/kubewarden-controller (go) versions < 1.33.0 is affected.
- Is there a fix for CVE-2026-29773? Yes. CVE-2026-29773 is fixed in 1.33.0. Upgrade to this version or later.
- Is CVE-2026-29773 exploitable, and should I be worried? Whether CVE-2026-29773 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-29773 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-29773? Upgrade
github.com/kubewarden/kubewarden-controllerto 1.33.0 or later.